Binding a custom method parameter to a class property

Is there any way to bind a class property to a method parameter inside that class so that there is a two way link when you click <kbd>Ctrl + Click</kbd>?

class Attachments extends Repository
{
    public Documents $documents;

    public function fromDocuments(callable $scope)
    {
        $this->scopeOnRepoProperty($scope, 'documents');
    }
}

I mean, that in that case second parameter documents in scopeOnRepoProperty() method should refer to property $documents.

The broader context:

The problem for me is that a large part of the code was very analogous, namely, most of the method scopeXXX/fromXXX does something like that, executes the method and sends the property repository to it as a parameter. i.e. in the example above, $scope($this->documents) is executed;
and additionally, if $this->documents is not initialized, a new instance is created.

So it's looks:

public function fromDocuments(callable $scope)
{
    if (!isset($this->documents)) {
        $this->documents = new Documents();
    }
    $scope($this->documents);
}

I wanted to save myself writing an if every time, creating a new object and calling a method, and I came up with the idea that I can do it with one method that will take a callable and the name of this property and from type reflection class name.

The code works fine, unfortunately I lost the bindings to these properties because of this. In the previous version it was $this->documents, so the link was there, but as it is now it is not.

I am wondering if there is any way I can achieve this. Any ideas?

> I wanted to save myself writing an if every time

    $scope($this->documents ??= new Documents());

This references both the property as well as the class you want to use there. That is often better than using a string that represents both (and also looses the references to both the concrete property and the concrete classname).

What you do there is also called lazy initialization. It has the problem that you have the new keyword within your classes that leads to hard to test code. Still thought it is an improvement over using the string.

You might also be interested for the new Generics support of @mixin in PhpStorm, you can find an example here:

• Support Generics Type in @mixin

This may allow you to skip the callable injection, but it's not entirely clear to me what you achieve by that, so this is only an additional hint, it must not match your needs.

References:

• PHP RFC: Null Coalescing Assignment Operator
• What is null coalescing assignment ??= operator in PHP 7.4
• Answer to "safely get array element value for defined and undefined indexes"